Polyepoxysuccinic Acid (PESA) CAS 51274-37-4

Introduction to Polyepoxysuccinic Acid

Polyepoxysuccinic Acid is supplied as a colorless to pale-yellow transparent liquid, a sodium polycarboxylate whose repeat unit bears two carboxyl groups plus one ether oxygen in the chain, with a molecular weight of 400–1,500 Da. The absence of phosphorus and nitrogen makes it a discharge-friendly scale inhibitor for cooling towers, boilers, and oilfield reinjection water operating under high-hardness, high-alkalinity, high-pH conditions.

Multiple –COOH groups chelate Ca²⁺, Ba²⁺, and Sr²⁺ at 400–500 mg CaCO₃ per gram of solids, while the ether oxygens distort growing CaCO₃ and CaSO₄ crystals so they stay dispersible. One practical caution: the 40% liquid is strongly alkaline (pH 9–12); dosing it through a line shared with acidic phosphonate blends or cationic polymers precipitates a calcium-PESA gel at the junction. Run a dedicated dosing line and flush after each batch.

Key Features of Polyepoxysuccinic Acid

• Phosphorus- and nitrogen-free backbone. No P or N atoms enter the discharge stream, so dosing loads do not feed algal eutrophication—clearing strict phosphorus discharge limits that constrain phosphonate programs.
• High-temperature, high-pH stability. The carboxyl/ether backbone resists hydrolysis at pH 9–12 and above 90 °C, holding CaCO₃ control in alkaline cooling towers where phosphonates lose activity.
• Strong calcium chelation. A chelation capacity of 400–500 mg CaCO₃/g (solids basis) sequesters Ca²⁺, Ba²⁺, and Sr²⁺; the threshold effect distorts crystal lattices at sub-stoichiometric doses.
• Ba/Sr sulfate control. Effective against BaSO₄ and SrSO₄ scale in oilfield reinjection water—a scale type most polycarboxylates handle poorly.
• Biodegradable structure. Shows meaningful degradation in OECD 301-type testing, unlike persistent phosphonates, simplifying environmental permitting for new plants.

Polyepoxysuccinic Acid Chemical & Physical Properties

Applications of Polyepoxysuccinic Acid

Open recirculating cooling water: Dosed at 5–20 mg/L active. Carboxyl groups chelate free Ca²⁺ while ether oxygens distort CaCO₃ nuclei, keeping heat-exchanger tubes clean under high alkalinity. Synergistic with HEDP and zinc salts at 2:1 to 3:1 ratios.

Boiler and high-temperature systems: Used at 10–30 mg/L. The backbone survives shell temperatures above 90 °C without hydrolysis, controlling CaCO₃ and CaSO₄ deposition where low-temperature polymers degrade.

Oilfield reinjection and produced water: Applied at 20–60 mg/L for BaSO₄ and SrSO₄ scale. Threshold distortion keeps sulfate scales dispersible at supersaturation levels that defeat simple phosphonate dosing.

RO membrane antiscalant: Dosed at 2–5 mg/L upstream of cartridge filters. Holds CaCO₃ and CaSO₄ supersaturation in a dispersed state across the membrane surface, extending CIP intervals.

Industrial detergent and cleaner builder: Incorporated at 0.5–2.0% as a phosphate-free builder. Chelates Ca²⁺ and Mg²⁺ in hard water, preventing soap scum without adding phosphorus to the wastewater load.

Storage & Safety Precautions for Polyepoxysuccinic Acid

Storage conditions. Store in sealed HDPE drums or IBC totes at 5–40 °C. Below 0 °C the 40% liquid may freeze; thaw at ambient temperature and agitate until homogeneous—no activity loss. Keep away from strong mineral acids, calcium-rich brines, and cationic polymers; contact at the bung or valve precipitates insoluble calcium-PESA gel.

Safety and PPE. GHS: Skin Irrit. 2 (H315); Eye Irrit. 2 (H319). The alkaline liquid irritates skin and eyes. Wear nitrile gloves and chemical-splash goggles during drum transfers. Spills are slippery; contain with sand and wash with copious water.

Transport classification. Non-DG. Not regulated under IMDG, IATA, or ADR. Ship as standard general cargo. Ensure drum bungs are torqued to prevent weeping during ocean freight.

Practitioner note: For incoming QC, verify solid content by oven-drying at 105 ± 2 °C to constant weight (≥40%), density ≥1.28 g/cm³ at 20 °C, and pH 9.0–12.0 in a 1% solution. Run the calcium chelation titration against standardised CaCl₂ at pH 11; a reading below 400 mg CaCO₃/g on solids flags a diluted or partially hydrolysed lot. Colour may drift from colorless to pale amber between batches without affecting performance.

Polyepoxysuccinic Acid FAQ

Q: How do I verify a delivered drum of PESA (CAS 51274-37-4)?

A: Four checks: solid content ≥40% by oven-dry at 105 °C; density ≥1.28 g/cm³ at 20 °C; pH 9.0–12.0 in 1% solution; calcium chelation ≥400 mg CaCO₃/g on solids against standardised CaCl₂ at pH 11. Colour from colorless to pale amber is normal batch variation. Reject if density reads below 1.25—this signals dilution.

Q: Why did a white gel plug form at my dosing-line junction?

A: The line was shared with an acidic phosphonate blend or a cationic polymer. Local pH drop or cationic contact precipitates calcium-PESA gel exactly at the mixing point. Switch PESA to a dedicated line, flush with water after each batch, and inspect check valves monthly. The gel does not redissolve at operating pH; mechanical cleaning is required.

Q: Can PESA control Ba/Sr sulfate scale where phosphonates fail?

A: Yes. The ether-oxygen backbone distorts BaSO₄ and SrSO₄ crystal lattices at threshold doses where phosphonates lose grip. Dose 20–60 mg/L in oilfield reinjection water. For mixed carbonate/sulfate scale, blend PESA with a phosphonate at 3:1 to 1:1—the combination covers both scale families at lower total dose than either alone.